On this episode of Catholic Review Radio, host Christopher Gunty speaks with architect Mauricio Cortés Sierra, one of the lead designers guiding the completion of Barcelona’s world‑famous Basilica de la Sagrada Familia. Cortés Sierra shares the remarkable story of a church begun in 1882, shaped by Antoni Gaudí’s visionary faith, and carried forward by multiple generations of artisans. He reflects on the recent completion of the Tower of Jesus Christ – the basilica’s highest point – and its deep spiritual symbolism, designed to remain humbly below the height of God’s creation. The conversation also explores how Gaudí used architecture to proclaim the Gospel, turning the basilica’s exterior into a “Bible in stone” and its interior into a luminous forest of prayer. With Pope Leo XIV set to help inaugurate the tower, this interview offers rare insight into how beauty, faith, and architecture come together to evangelize the modern world.